Add bower for managing script dependencies.

Bower is a system for magaging versions of javascript libraries. This makes it
easier to get an overview of which libraries that are in use and makes the
upgrade process much easier.

To implement this the Grunt configuration has been updated and also fixed lots
of jshint warnings.
Rename statistics page to listTags
Add d3js visualization

Add a new start page that uses d3js for visualizing tags.
Some tweaks to the jshint configuration to make it pass validation.